secondary - heatwaves - prevention

HEAT WAVESPREVENTION

SECONDARY LEVEL

e-Learning for the Prevention, Preparedness and Response to Natural Disasters

IN THIS LESSON YOU WILL LEARN

●What are heat waves?●What causes heat waves?●Signs of heat waves.●The impact of heat waves. What to be aware of?●The most important heatwaves in the world throughout

history


WHAT IS A HEAT WAVE?

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Do you know what are heatwaves?


The weather is warming up in the summertime, the

days are becoming longer and there's more time to be outside doing all

kinds of fun things! But if you're going to

be out in the sun, especially on a hot day, you need to

stay safe

Do you know what are heatwaves?


Weather is not always the same. You can tell so by looking outside or find out about the weather by watching weather forecasts on the TV, Internet, Mobile phone apps, Radio and so on.

The weather is warming up in the summertime, the

days are becoming longer and there's more time to be outside doing all

kinds of fun things! But if you're going to

be out in the sun, especially on a hot day, you need to

stay safe

Do you know what a heatwave is?


HEAT is energy that is transferred from one body to another because of a difference in temperature.

Do you know what heatwaves are?


HEAT WAVES are extended periods of unusually hot weather that affect human and animal health. A heat wave can be an extended period of days with higher than normal temperatures.

Do you know what heatwaves are?


HEAT WAVES are extended periods of unusually hot weather that affect human and animal health. A heat wave can be an extended period of days with higher than normal temperatures.

However, a heat wave can also be shorter in length, but with abnormally high temperatures which bring negative effects on human health, as well as on nature.

What causes a heat wave?


What causes a heatwave?


CLIMATE CHANGE is one of the most important factors which cause heat waves and increase their intensity and frequency. Heat waves are becoming hotter, lasting longer and occurring more often. In the last decade, record hot weather has occurred three times more often than cold weather records.



CLIMATE CHANGE is one of the most important factors which cause heat waves and increase their intensity and frequency. Heat waves are becoming hotter, lasting longer and occurring more often. In the last decade, record hot weather has occurred three times more often than cold weather records. Climate change is also making heat waves worse in terms of their impacts on people, property, communities and the environment



AIR PRESSURE

DEPLETION OF OZONE LAYER

THERE ARE TWO MAIN REASONS WHY HEAT WAVES OCCUR



The main reason why heat waves occur is closely connected with the Jet stream. The jet stream occurs in the atmosphere at approximately 11 km height between areas of high and low air pressure. The air on the edges of the Jet stream is likely to be warmer. Since the high atmospheric pressure is not marked by lots of clouds, the surface of the earth can easily get warmer than usual. In this case, because the layer of cloud above the earth is very thin or does not exist at all, the possibility to cool the earth disappears completely and here the conditions for a heat wave are created.

AIR PRESSURE



The Ozone layer covers the Earth from direct and very harmful sun rays. Depletion of this layer can bring harm not only for people (various types of cancer can occur), but also for the environment (the land may become drier; the temperature of the air is rising, etc.). So, we should all be very careful about the environment in order not to make the Ozone layer thinner.

Depletion of the Ozone Layer

Signs of heat waves


Signs of heat waves


We should all be very careful about the environment in order not to make the Ozone layer thinner.

Everyone should know how to behave and what to do if a heat wave occurs.

Signs of heat waves


We can distinguish several features of heat waves:

Signs of heat waves



Unseasonable Warmth

Signs of heat waves



Unseasonable Warmth

Humidity

Signs of heat waves



Unseasonable Warmth

Humidity

Duration

Signs of heat waves


UNSEASONABLE WARMTH Heat waves are generally characterized by

periods of unseasonable warmth. This is defined in different ways in different countries. Although this can also happen and be common during the cooler months, it is generally considered a heat wave during the warm months when the air becomes uncomfortably warm. For example, the air temperature in your town or city reaches 28-30◦ C for couple of days. The weather forecast on TV or radio does not promise any changes – according to forecaster such temperature will remain during the next 4-5 days. So such a period can be called a heat wave

Signs of heat waves


UNSEASONABLE WARMTH

Heat waves are generally characterized by periods of unseasonable warmth.

Heat waves are generally characterized by periods of unseasonable warmth. This is defined in different ways in different countries. Although this can also happen and be common during the cooler months, it is generally considered a heat wave during the warm months when the air becomes uncomfortably warm. For example, the air temperature in your town or city reaches 28-30◦ C for couple of days. The weather forecast on TV or radio does not promise any changes – according to forecaster such temperature will remain during the next 4-5 days. So such a period can be called a heat wave

Signs of heat waves


UNSEASONABLE WARMTH

Heat waves are generally characterized by periods of unseasonable warmth.

This is defined as being at least 9 degrees Celsius higher than the average temperature of a region during the same time of year.

Heat waves are generally characterized by periods of unseasonable warmth. This is defined in different ways in different countries. Although this can also happen and be common during the cooler months, it is generally considered a heat wave during the warm months when the air becomes uncomfortably warm. For example, the air temperature in your town or city reaches 28-30◦ C for couple of days. The weather forecast on TV or radio does not promise any changes – according to forecaster such temperature will remain during the next 4-5 days. So such a period can be called a heat wave

Signs of heat waves


UNSEASONABLE WARMTH

Signs of heat waves


HUMIDITY

Humidity measures how much moisture is in the air

Signs of heat waves


HUMIDITY


Warm air holds more moisture than cold air, and at higher temperatures, humidity can be extremely uncomfortable.

Signs of heat waves


HUMIDITY


Warm air holds more moisture than cold air, and at higher temperatures, humidity can be extremely uncomfortable.

The reason for this is that the human body cools itself by the evaporation of sweat. When the humidity is too high, sweat does not effectively evaporate, and people can easily overheat

Signs of heat waves


HUMIDITY

Heat waves can lead to DROUGHT.

Image courtesy of dan at FreeDigitalPhotos.net

Signs of heat waves


HUMIDITY


Drought and heat, in fact, are inter-related. According to scientists, in regions where moisture of the air and soil is reduced, naturally, the air temperature rises, and this can result in longer and more intense heatwaves and droughts.

Image courtesy of dan at FreeDigitalPhotos.net

Signs of heat waves


HUMIDITY


Drought and heat, in fact, are inter-related. According to scientists, in regions where moisture of the air and soil is reduced, naturally, the air temperature rises, and this can result in longer and more intense heatwaves and droughts.

If there is enough water in the soil, cooling connected with the evaporation can slow the severity of an outcoming heatwave, preventing the occurrence of extreme heatwaves. Image courtesy of dan at FreeDigitalPhotos.net

Signs of heat waves


HUMIDITY

Heatwaves occur when a ridge of high pressure sits over a region for an extended period of time, bringing down dry, hot air to the ground. As the air sinks, it warms and compresses and is very hot by the time it reaches the surface.

Signs of heat waves


HUMIDITY


This hot air quickly heats up the ground, which raises the air temperature. Since the centre of high pressure areas are usually cloud-free, the direct sunlight raises daytime temperatures further.

Signs of heat waves


HUMIDITY


This hot air quickly heats up the ground, which raises the air temperature. Since the centre of high pressure areas are usually cloud-free, the direct sunlight raises daytime temperatures further.

If humidity is high, temperatures do not cool much at night. Night-time heat greatly contributes to overall humidity.

Signs of heat waves


DURATION

In addition to unseasonably warm temperatures and high humidity, a heat wave is characterized by its duration.

Signs of heat waves


DURATION

One unusually warm day does not make a heat wave. However, when that heat stays around for two or more days, it is considered a heat wave. The longer a mass of high atmospheric pressure sits on an area, the warmer it can get. In this way, heat waves last many days or even several weeks and can be particularly dangerous.

In addition to unseasonably warm temperatures and high humidity, a heat wave is characterized by its duration.

Signs of heat waves - DURATION


Signs of heat waves


Which picture do you think shows hot summer weather and which shows a heat wave?

THE IMPACT OF HEAT WAVES. What to be aware of?.


The impact of heat waves


Each summer, different areas of the world experience unseasonably warm temperatures for extended periods of time. Many news stories follow these heat waves, pointing out several public health dangers. Heat waves have been known to cause medical problems and even deaths. Additionally, heat waves result in higher energy consumption, as people use more electricity to power air conditioners in their homes, work places and cars.

What to be aware of:


Heat waves are a particularly important risk for people living in cities because metropolitan areas can be significantly warmer than neighbouring countryside areas. Dense urban areas, such as inner city environments, may be 1 to 3°C hotter than surrounding areas. This phenomenon is known as the “Urban Heat Island” and occurs because of a decreased amount of plants and increased areas of dark surfaces in urban environments (sidewalks, roads, etc.), in addition to the heat produced from vehicles and generators. The Urban Heat Island effect is generally more prominent during the night than the day, so its major impact is to increase the likelihood of extreme high minimum temperatures.



Heat waves can be dangerous for adults over 65, children under 4, and people who suffer from heart disease. Any time a person is exposed to heat, they are in danger of suffering from heat exhaustion and heat stroke. These heat-related illnesses have killed thousands over the last 100 years.



Going into more details, we have to mention that elderly people are particularly at risk during a heatwave. This is because ageing decreases tolerance to heat:




•thirst is sensed late,




•thirst is sensed late, •the sweating reaction is delayed,




•thirst is sensed late, •the sweating reaction is delayed,•and the number of sweating glands is

reduced.



Heat waves can have direct and indirect impacts on people’s health.

The direct impact of heat waves on human health


The main health effects of a heat wave result from the body not being able to effectively cool itself. Without proper cooling, a person can suffer from heat exhaustion and eventually heat stroke. Without enough fluid intake, a person can suffer dehydration. This often occurs when the body sweats out more water than it takes in. The elderly, particularly those who have problems with their heart, can be especially vulnerable during a heat wave.



The higher body temperature occurs when natural body's cooling process is affected by the heatwave, when the body cannot evaporate itself properly by sweating, especially if humidity is high.

The main health effects of a heat wave result from the body not being able to effectively cool itself.



If core body temperature rises to 38 degerees for several hours, heat exhaustion occurs and mental and physical capacity becomes impaired.




If core body temperature rises to 42, even for just a few hours, heat stroke and death can result.




Heat waves lasting even a few days, especially if coupled with high night-time temperatures (for example, above 20°C or lower 30°C), can cause serious health impacts.




The warm nights are particularly important because our bodies do not get the chance to recover.




The warm nights are particularly important because our bodies do not get the chance to recover.

It is the cumulative effects over a few days of an intense heat wave that lead to serious health impacts and deaths – and people tend to see these after the worst of the heat wave has passed.



In summary, we can note that:• People can suffer from heat cramps, heat exhaustion or even

heat stroke




heat stroke• When a heat wave occurs the body can lose lots of water –

dehydration may occur




heat stroke.• When a heat wave occurs the body can lose lots of water –

dehydration may occur.• Also, when trying to cool yourself during the intensive heat by

drinking lost of cold water you can catch the flu



* Some information which help you to recognise heat cramps:

- They are muscular pains and spasms that usually occur in the legs. Such spasms can occur even while having rest or at night time. - Panic can occur because people do not know how to behave in such a situation.

Heat crampsHeat cramps are often an early sign that the body is having trouble with

the heat.



Signs which will help to recognise that a person is suffering from the heat exhaustion: - cool, moist, pale, flushed skin; - headache; - nausea; - dizziness; - weakness and exhaustion.

Heat exhaustionHeat exhaustion is a more severe condition

than heat cramps.



Heat exhaustion

Heat exhaustion is a more severe condition than heat cramps.

Heat exhaustion often affects athletes, firefighters, and factory workers, those wearing heavy clothing in a hot, humid environment.



Signs which will help to recognise that a person is suffering from the heat stroke are: - extremely high body temperature; - red skin which may be dry or moist; - changes in consciousness; - rapid, weak pulse and rapid, shallow

breathing; -vomiting

Heat stroke

Heat stroke is a life-threatening condition that usually occurs by ignoring the signals of heat exhaustion. Heat stroke develops when the body’s systems are

overwhelmed by heat and begin to stop functioning.



Heat stroke and Heat exhaustion

Heat exhaustion and heat stroke are very similar. That is why it is sometimes difficult to identify and separate what exactly happened to a person. The main differences between heat exhaustion and heat stroke are:



* Signs which will help to recognise that a person is suffering from dehydration are:

- increased thirst;- increased sweating;- dry mouth and swollen tongue;- weakness;- confusion;- fainting;- head aches.

Dehydration Dehydration is the loss of large amounts of liquid from the body. * It occurs when the amount of water leaving the body is greater than the amount being taken in.

The indirect impact of heat waves on human health


There are a number of indirect effects that extreme heat has on our health:



There are a number of indirect effects that extreme heat has on our health:• It can be various infectious diseases transmitted by insects.



There are a number of indirect effects that extreme heat has on our health:• It can be various infectious diseases transmitted by insects.• It is very important to mention that extreme heat can lead to power outages, which in turn can lead to a loss of air-conditioning, refrigeration and cooling, affecting homes and food outlets.



There are a number of indirect effects that extreme heat has on our health:• It can be various infectious diseases transmitted by insects.• It is very important to mention that extreme heat can lead to power outages, which in turn can lead to a loss of air-conditioning, refrigeration and cooling, affecting homes and food outlets. • Harmful bacteria in food grow more quickly in warm temperatures, increasing the possibility of gastrointestinal illnesses from food that is kept in such warm conditions without refrigeration.

The impact of heat waves on infrastructure


Extreme heat can have significant impacts on infrastructure and essential service, especially electricity transmission and transport systems. Heat waves test ability of the infrastructure to withstand the pressures of increased energy demand (in particular from use of air conditioners). Electricity transmission can also be affected as transmission lines may become so hot that they expand and can hang dangerously low and have to be switched off.

The impact of heat waves on the environment


Heat waves can cause significant damage to nature and the environment:



Heat waves can cause significant damage to nature and the environment:Some species of animals can disappear.



Heat waves can cause significant damage to nature and the environment:Some species of animals can disappear.New species of insects and animals that are heat-resistant appear.



Heat waves can cause significant damage to nature and the environment:Some species of animals can disappear.New species of insects and animals that are heat-resistant appear.Other animals change their usual lifestyle and behaviour.



Heat waves can cause significant damage to nature and the environment:Some species of animals can disappear.New species of insects and animals that are heat-resistant appear.Other animals change their usual lifestyle and behaviour.Fires in open places (forests, meadows) become more frequent

The impact of heat waves on nature


Like human beings, animals can also suffer, particularly when they are left in the direct sun and they do not get adequate water. Domestic animals and poultry are especially vulnerable to heat wave.

Temperature, wind speed, humidity, and solar radiation can all contribute to heat stress in livestock.

In periods of extreme heat, birds may lose up to 5% of their body mass per hour and rapidly reach their limit of dehydration tolerance.



Marine organisms are also affected by the impacts of severe heat. Heatwaves can occur in the surface waters of the ocean, sometimes leading to dramatic impacts on marine ecosystems. When coral reefs are subject to sea surface temperatures more than 1-2°C above average summer maximum temperatures, the corals can bleach and die. Bleaching events on the Great Barrier Reef have occurred repeatedly since the late 1970s where none were observed before 1970. Bleaching events have contributed to the decline in coral cover observed from 1985 to 2002. However, corals are not the only marine systems to be affected by heatwaves. Mortality and reduced reproduction have also been observed in some marine species. Extreme heat affects each ecosystem differently, however; it may take a long time to recover after the heatwave or the ecosystem may never return to their original state



Extreme heat has a negative impact on grain crops (maize, wheat, and soya) as well as fruit trees (apple, cherry, pear) and may affect the quality of the fruit. Other plants also feel the negative impact of heat waves.



It is now well known that many bumblebee species are threatened in Europe and in North America.

Various theories have been presented to explain this regression. Some scientists say that many bumblebee species are disappearingis due to synthetic fertilisation.

However, since 2002, it has been observed that a great number of situations where local droughts and heat waves occurred in France, UK, Scandinavia, Turkey, have lead to very strong local reductions of the bumblebee fauna.

As they are the most exposed to heat waves, they can be the most sensitive to this risk

The impact of heat waves on wildfires


If weather gets really hot and dry it can increase the possibility of wildfiresWildfire has very negative impact on wildlife•Animals cannot excape



If weather gets really hot and dry it can increase the possibility of wildfiresWildfire has very negative impact on wildlife•Animals cannot excape•Habitats of local animals will be destroyed



If weather gets really hot and dry it can increase the possibility of wildfiresWildfire has very negative impact on wildlife•Animals cannot excape•Habitats of local animals will be destroyed•Different plants and plantlife are either destroyed completely or need a great amount of time to recover



If weather gets really hot and dry it can increase the possibility of wildfiresWildfire has very negative impact on wildlife•Animals cannot excape•Habitats of local animals will be destroyed•Different plants and plantlife are either destroyed completely or need a great amount of time to recover•Fires get hotter, bigger and more frequent



If weather gets really hot and dry it can increase the possibility of wildfiresWildfire has very negative impact on wildlife•Animals cannot excape•Habitats of local animals will be destroyed•Different plants and plantlife are either destroyed completely or need a great amount of time to recover•Fires get hotter, bigger and more frequent •Big fires are changing the ecosystem balance



If weather gets really hot and dry it can increase the possibility of wildfiresWildfire has very negative impact on wildlife•Animals cannot excape•Habitats of local animals will be destroyed•Different plants and plantlife are either destroyed completely or need a great amount of time to recover•Fires get hotter, bigger and more frequent •Big fires are changing the ecosystem balance•Entire forests are being destroyed and it takes hundreds of years for mature forests to return

The most important heatwaves in the world throughout history




Marble Bar heatwave, 1923-1924. The world record for the longest sequence of days above 100◦ Fahrenheit (or 37.8◦ on the Celsius scale) is held by Marble Bar in the inland Pilbara district of Western Australia. The temperature, measured under standard exposure conditions, reached or exceeded the century mark every day from 31st October 1923 to 7th April 1924, a total of 160 days.


The „Dust Bowl“years of 1930-1936. Some of the hottest summers on record in the United States. Nationally, around 5000 deaths were associated with the heatwave. What lead to the “Dust Bowl”? 1) The lack of rain that parched the earth and killed vegetation;2) Poor land management.




The famous summer of ’76 in the UK. It was a period of nine weeks; the weather was consistently dry, sunny and hot. It should also be remembered that summer of the 1976 marked the culmination of a prolonged drought which had begun in April, 1975



Europe, 2003. More than 20 000 people died after a record-breaking heatwave left Europe sweltering in August 2003. The period of extreme heat is thought to be the warmest for up to 500 years, and many European countries experienced their highest temperatures on record.



Lithuania, 2006. Extreme heat affected wildlife in Kuršių Nerija, the Curonian Spit National Park. At that time 236 hectares of the territory of the National park burned away in just in five days. Even today the area is only partially replanted. Further wildfires occurred after the 2006 fire and the soil was damaged and is not as heat-resistant now as it was before.



Drought and wildfires in Russia in 2010. After record warm temperatures, drought, wildfires, and poor air quality during July 2010, the dismal conditions continued through mid-August across western Russia. At the beginning of August, 676 square miles (1 740 square km) were burning with over 600 active fires.

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